rcu: Move rcu_barrier_mutex to rcu_state structure
In order to allow each RCU flavor to concurrently execute its
rcu_barrier() function, it is necessary to move the relevant
state to the rcu_state structure. This commit therefore moves the
rcu_barrier_mutex global variable to a new ->barrier_mutex field
in the rcu_state structure.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index ca7d167..ff992ac 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -71,6 +71,7 @@
.onofflock = __RAW_SPIN_LOCK_UNLOCKED(&sname##_state.onofflock), \
.orphan_nxttail = &sname##_state.orphan_nxtlist, \
.orphan_donetail = &sname##_state.orphan_donelist, \
+ .barrier_mutex = __MUTEX_INITIALIZER(sname##_state.barrier_mutex), \
.fqslock = __RAW_SPIN_LOCK_UNLOCKED(&sname##_state.fqslock), \
.n_force_qs = 0, \
.n_force_qs_ngp = 0, \
@@ -155,10 +156,6 @@
unsigned long rcutorture_testseq;
unsigned long rcutorture_vernum;
-/* State information for rcu_barrier() and friends. */
-
-static DEFINE_MUTEX(rcu_barrier_mutex);
-
/*
* Return true if an RCU grace period is in progress. The ACCESS_ONCE()s
* permit this function to be invoked without holding the root rcu_node
@@ -2303,7 +2300,7 @@
init_rcu_head_on_stack(&rd.barrier_head);
/* Take mutex to serialize concurrent rcu_barrier() requests. */
- mutex_lock(&rcu_barrier_mutex);
+ mutex_lock(&rsp->barrier_mutex);
smp_mb(); /* Prevent any prior operations from leaking in. */
@@ -2380,7 +2377,7 @@
wait_for_completion(&rsp->barrier_completion);
/* Other rcu_barrier() invocations can now safely proceed. */
- mutex_unlock(&rcu_barrier_mutex);
+ mutex_unlock(&rsp->barrier_mutex);
destroy_rcu_head_on_stack(&rd.barrier_head);
}
diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index d1ca442..7641aec 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -400,6 +400,7 @@
struct task_struct *rcu_barrier_in_progress;
/* Task doing rcu_barrier(), */
/* or NULL if no barrier. */
+ struct mutex barrier_mutex; /* Guards barrier fields. */
atomic_t barrier_cpu_count; /* # CPUs waiting on. */
struct completion barrier_completion; /* Wake at barrier end. */
raw_spinlock_t fqslock; /* Only one task forcing */
